In the field of internal medicine, the treatment of stomach ulcer and duodenal ulcer has made a great transition from treatment by means of surgical procedures to noninvasive drug treatments as a result of progress made in drugs such as H2-antagonists, gastric inhibitors and the like.
On the other hand, there has been an increase in subjects who, while showing no signs of ulcer in endoscopic examinations, nevertheless complain of symptoms such as vomiting, nausea, gastric fullness, heavy stomach, heartburn, anorexia, upper abdominal pain and the like (such subject is referred to collectively as “subjects with indefinite complaint”). Such indefinite complaint is generally diagnosed on the basis of the symptoms reported by the subject, and it is extremely difficult to diagnose such complaint in an objective and quantitative manner. Furthermore, the difficulty of such diagnosis delays appropriate treatment, and also causes a deterioration in the quality of life (QOL) of such subject with indefinite complaint. It has recently been found that such indefinite complaint reported by subject have a close correlation with a lowering of the gastric emptying rate (GER), and it has been reported that a lowering of the gastric emptying rate is observed in approximately half of all subjects suffering from indefinite complaints.
Accordingly, it would appear that if it were possible to measure the gastric emptying rate easily and with high precision without imposing a burden on the subject, this would make a great contribution to the appropriate diagnosis and treatment of the subject suffering from indefinite complaint.
However, conventional methods for measuring the gastric emptying rate are expensive, or are invasive so that such methods impose a psychological and physical burden on the subject. Moreover, the time for which the subject is constrained is long in the case of such methods, and the measurement precision is insufficient. For example, among conventional methods for measuring the gastric emptying rate, the isotope method (e.g., scintigraphy or the like) uses a radioactive isotope; as a result, the administration of this method is complicated. Furthermore, since this method requires an expensive γ-ray camera, the use of this method is restricted to special facilities. Furthermore, in the case of the X-ray impermeable marker method, the marker is not discharged from the stomach simultaneously with the food contents, but is instead discharged from the stomach after all of the food contents have bee discharged; as a result, the actual gastric emptying function cannot be accurately examined. Furthermore, in the case of the acetaminophen method, there is a danger of drug allergy and liver damage due to the side effects of acetaminophen; furthermore, since this drug is subject to other effects in the body such as absorption in the small intestine, metabolization by the liver, excretion from the kidneys and the like, the gastric emptying function cannot be accurately examined. Furthermore, since the concentration of acetaminophen in the blood is measured after administering acetaminophen, the invasive procedure of blood collection is required.
Furthermore, methods such as a method in which the endogastric volume and saburra are measured by means of ultrasonic waves (ultrasound method), a method in which the gastric emptying rate is measured by MRI (magnetic resonance imaging method), a method in which the gastric motor function is evaluated by measuring an electrogastrogram (elctrogastrography) and the like have also been proposed as other methods for measuring the gastric emptying rate; however, such methods suffer from the following problems: (i) There are problems in the precision of the diagnostic method, (ii) there are no fixed criteria, so that evaluations vary according to the evaluator, and (iii) the subject must be constrained for a long period of time while the diagnosis is being made.